MTLBuffer

A MTLBuffer object can be used only with the MTLDevice that created it. Don’t implement this protocol yourself; instead, use the following MTLDevice methods to create MTLBuffer objects:

• newBufferWithLength:options: creates a MTLBuffer object with a new storage allocation.

• newBufferWithBytes:length:options: creates a MTLBuffer object by copying data from an existing storage allocation into a new allocation.

• newBufferWithBytesNoCopy:length:options:deallocator: creates a MTLBuffer object that reuses an existing storage allocation and does not allocate any new storage.

The Metal framework doesn’t know anything about the contents of a MTLBuffer, just its size. You define the format of the data in the buffer and ensure that your app and your shaders know how to read and write the data. For example, you might create a struct in your shader that defines the data you want to store in the buffer and its memory layout.

If you create a buffer with a managed resource storage mode (MTLStorageModeManaged), you must call didModifyRange: to tell Metal to copy any changes to the GPU.